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PRGD-SVX01F-EN

Figure 8. Air removal cycle

Pump-out Operating Sequence

As the purge control system detects the presence of
non-condensables in the purge tank, it initiates a
pump-out cycle. The pump-out solenoid valve, the
exhaust solenoid valve, and the pump-out compressor
cycle On and Off as needed to remove the non-
condensables.

Non-condensable Pump-out Algorithm

The controller uses the non-condensable pump-out
algorithm to determine when to initiate, control, and
terminate a pump-out cycle to remove air from the
purge tank. The purge refrigerant compressor suction
temperature sensor serves as the feedback to this
control algorithm. The compressor suction
temperature pump-out initiate and pump-out terminate
values are calculated by the purge control and are a
function of the purge liquid temperature.

The refrigerant used in the purge refrigeration circuit,
R-404A, is metered into the purge tank coil by a
constant-pressure regulating expansion valve. The
valve automatically controls the purge suction pressure
at a constant value of 34 psia (234.4 kPaA). Therefore,

refrigerant is metered into the coil as a two-phase
refrigerant mixture at a constant saturation
temperature of approximately -16°F (-8.9°C).

The cold coil creates a low vapor pressure near its
outside surface, which draws refrigerant from the
chiller condenser into the purge tank and to the coil
surface. When the refrigerant gets close enough to the
coil surface, it condenses into a liquid. Since liquid
refrigerant requires less volume than it does in a
gaseous form, additional refrigerant enters the purge
tank to fill the void and, in turn, condenses. This
mechanism is known as a

thermal siphon

.

As the chiller refrigerant condenses, heat is transferred
into the purge coil through the latent heat of
condensation. The compressor suction temperature
sensor monitors this heat transfer.

Air and other gases carried with the chiller refrigerant
vapor do not condense on the coil. Instead, they
accumulate in the purge tank, effectively acting to
insulate and inhibit the flow of refrigerant to the cold
coil surface. The thermal siphon rate is reduced and,
consequently, so is the amount of heat transfer. A
corresponding reduction occurs in the temperature of

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Summary of Contents for PRGD series

Page 1: ...raining Improperly installed adjusted or altered equipment by an unqualified person could result in death or serious injury When working on the equipment observe all precautions in the literature and on the tags stickers and labels that are attached to the equipment July 2017 P PR RG GD D S SV VX X0 01 1F F E EN N EarthWise Purge System with Tracer AdaptiView Control for Water Cooled CenTraVac Chi...

Page 2: ... jo ob b b be ei in ng g u un nd de er rt ta ak ke en n c co ou ul ld d r re es su ul lt t i in n d de ea at th h o or r s se er ri io ou us s i in nj ju ur ry y T Te ec ch hn ni ic ci ia an ns s i in n o or rd de er r t to o p pr ro ot te ec ct t t th he em ms se el lv ve es s f fr ro om m p po ot te en nt ti ia al l e el le ec ct tr ri ic ca al l m me ec ch ha an ni ic ca al l a an nd d c ch he ...

Page 3: ...es ss su ur re e F Fa ai il lu ur re e t to o f fo ol ll lo ow w i in ns st tr ru uc ct ti io on ns s b be el lo ow w c co ou ul ld d r re es su ul lt t i in n a an n e ex xp pl lo os si io on n w wh hi ic ch h c co ou ul ld d r re es su ul lt t i in n d de ea at th h o or r s se er ri io ou us s i in nj ju ur ry y o or r e eq qu ui ip pm me en nt t d da am ma ag ge e S Sy ys st te em m c co on nt...

Page 4: ...ce 21 Operator Interface 23 Reports 23 Log Sheet 23 Purge Operating Modes 23 Settings 24 Purge Settings 24 Manual Control Settings 24 Alarms 24 Maintenance 25 Weekly Maintenance 25 Semi Annual Maintenance 25 Annual Maintenance 25 Replacing the Filter Drier Assembly 25 Inspecting the Moisture Indicator 26 Maintaining the Moisture Indicating Sight Glass 27 Removing Air After Servicing the Chiller 27...

Page 5: ...dentifies the operating components and option for that specific unit see EarthWise Purge System Model Number p 6 for detailed information The model number is also printed on the unit nameplate It is important to refer to the model number when ordering parts or requesting technical assistance Figure 1 Example of a typical nameplate ...

Page 6: ...4 with Hersite Condensing Unit S Special Digit 6 Control Options 0 Without Power Supply 1 With Power Supply 2 Standard Condenser Pressure Cutout 3 ASME Condenser Pressure Cutout Digit 7 Control Interface 0 Chiller Interface 1 Purge Interface Digit 8 Frequency 1 60 Hz 2 50 Hz Digit 9 Vacuum Pump A Standard Vacuum Pump B High Vacuum Pump C Industrial Vacuum Pump Digit 10 11 Design Sequence A0 Origin...

Page 7: ...unted on the chiller Its purpose is to remove non condensable materials that have leaked into the machine N No ot te e For convenience the term air is often used in describing non condensables removed by the purge system although any other non condensable materials that may exist in the chiller are also removed by the purge system Reference Sources The following reference documents may be helpful ...

Page 8: ...he purge tank When the purge refrigeration system is running refrigerant from the chiller condenser is attracted to the cold surface of the purge evaporator When the gaseous refrigerant contacts the surface of the purge evaporator coil it condenses into a liquid leaving a partial vacuum behind More refrigerant vapor from the chiller condenser migrates to the purge tank to fill the vacuum The liqui...

Page 9: ...lief device fusible plug 4 Pump out solenoid valve 5 Automatic expansion valve 6 Carbon tank 7 Carbon tank temperature sensor 8 Carbon tank heater 9 Exhaust solenoid valve 10 Pump out compressor 11 Float switch 12 Compressor suction temperature sensor 13 Chiller refrigerant return line 14 Filter drier canister P Pu ur rg ge e S Sy ys st te em m O Ov ve er rv vi ie ew w ...

Page 10: ...sure relief valve 3 Exhaust solenoid valve 4 Pump out compressor 5 Carbon tank heater 6 Automatic expansion valve 7 Pump out solenoid valve 8 Pressure relief device fusible plug 9 Carbon tank 10 Purge tank 11 Condensing unit 12 Chiller refrigerant supply line P Pu ur rg ge e S Sy ys st te em m O Ov ve er rv vi ie ew w ...

Page 11: ...ugh idle chillers chillers installed outdoors or in unconditioned spaces or any application that may cause very low condenser water temperatures Carbon Tank and Regeneration Subsystem The discharge from the pump out compressor is piped through the carbon tank The special carbon in the tank effectively scrubs and collects refrigerant molecules from the non condensable gas before the gas passes thro...

Page 12: ...ank of the purge system It provides feedback to the carbon regeneration algorithm The sensor and the controller function much the same as a thermostat to control the carbon tank heater L Li iq qu ui id d l le ev ve el l s se en ns so or r This sensor resides in the purge control panel It monitors the status of the normally closed float switch which is mounted in the bottom of the purge tank If an ...

Page 13: ...it only when needed to remove non condensables rather than running it continuously The Adaptive mode requires historical operating data so that the controller can make optimal decisions regarding how to run the purge refrigeration circuit in the future On initial start up of a chiller that is in Adaptive mode the purge refrigeration circuit runs continuously for 168 hours 7 days The chiller compre...

Page 14: ...ur Pumpout Time 8 minutes No Off cycle During the purge refrigeration circuit Off cycle the time remaining is displayed as Time Until Next Purge Run in the Log Sheet that you can view from the Tracer AdaptiView display refer to Log Sheet p 23 If the compressor is turned Off during the purge refrigeration circuit Off cycle the purge transfers to Adaptive Mode Procedure Chiller Compressor Off Figure...

Page 15: ...ith the chiller On over the last 7 days N No ot te e These two values can be seen on the Tracer AdaptiView display Figure 5 Adaptive chiller OFF flow chart The purge will be shut down for a corresponding period of time as shown in the following table Pumpout Time with chiller On or Off over the last 24 hours or daily average over the last 7 days whichever is greater Purge Off cycle duration Pumpou...

Page 16: ... F 37 8 C condensing the purge refrigeration cycle should have the temperatures shown in the following figure for Locations 1 5 N No ot te e To troubleshoot the system by taking these temperatures refer to Taking Surface Temperature Measurements p 30 Figure 6 Purge refrigeration circuit showing temperatures at various locations in operating cycle Temperatures at numbered locations 1 After expansio...

Page 17: ...urning to the purge condensing unit compressor suction has a high superheat heat added past the point of evaporation because of the heat removed from the condensing chiller refrigerant vapor in the purge tank As air accumulates in the purge tank it displaces the chiller refrigerant vapor and decreases the amount of coil surface that is exposed to the vapor Less heat is removed from the vapor and t...

Page 18: ...of 34 psia 234 4 kPaA Therefore refrigerant is metered into the coil as a two phase refrigerant mixture at a constant saturation temperature of approximately 16 F 8 9 C The cold coil creates a low vapor pressure near its outside surface which draws refrigerant from the chiller condenser into the purge tank and to the coil surface When the refrigerant gets close enough to the coil surface it conden...

Page 19: ...ions are met a carbon regeneration cycle is NOT in process and the refrigeration circuit is on If at any time except as described above the purge refrigerant compressor suction temperature drops below the pump out initiate value the following sequence is initiated by the controls The controller starts the pump out compressor and opens the exhaust solenoid valve After 5 seconds the pump out solenoi...

Page 20: ...ting conditions and operating schedule Carefully monitor the purge pump out activity for each chiller for an appropriate period of time one week or more in order to establish a baseline value for a Purge Daily Pumpout Limit that is appropriate for that specific installation Set the Purge Daily Pumpout Limit high enough to avoid nuisance trips but low enough to trigger an alarm diagnostic should th...

Page 21: ...tank capacity remaining 100 80 500 100 84 The purge controls may initiate a carbon tank regeneration cycle when the remaining carbon tank capacity is calculated to be less than 80 percent However the continued stable operation of the chiller is always more important than the regeneration of the carbon tank Therefore the following rules apply 1 If the Daily Pump out Limit is disabled a regeneration...

Page 22: ...nostic is to identify a failed heater or temperature sensor It prevents automatic regeneration from occurring but a service technician can initiate a manual regeneration for testing purposes All other purge algorithms continue to function If the carbon tank temperature does not reach the minimum regeneration temperature setpoint within four hours the controller generates a non latching diagnostic ...

Page 23: ...g 168 hour window that the chiller was operating You can use it to help determine if a leak is present on the high side or the low side of the chiller P Pu um mp po ou ut t C Ch hi il ll le er r O On n 7 7 D Da ay ys s Indicates the percentage of the total purge pump out time during the past seven days that occurred while the chiller was operating You can use it to help determine if a leak is pres...

Page 24: ... range is from 1 to 50 minutes the factory default is 10 minutes D Di is sa ab bl le e D Da ai il ly y P Pu um mp po ou ut t L Li im mi it t Use it to disable alarms for a specified time that are associated with exceeding the daily pumpout limit This is useful when large amounts of purging are needed following chiller servicing or operator error The range is from 0 to 72 hours the factory default ...

Page 25: ...e ex xc ce ee ed d 3 30 00 0 F F 1 15 50 0 C C T To o a av vo oi id d p po os ss si ib bl le e s sk ki in n b bu ur rn ns s s st ta ay y c cl le ea ar r o of f t th he es se e s su ur rf fa ac ce es s I If f p po os ss si ib bl le e a al ll lo ow w s su ur rf fa ac ce es s t to o c co oo ol l b be ef fo or re e s se er rv vi ic ci in ng g I If f s se er rv vi ic ci in ng g i is s n ne ec ce es ss ...

Page 26: ...drain valve Then check for leaks 10 Release the pressure remove hoses and replace all valve caps 11 Set the purge operating mode to On and wait for the purge pump out compressor to start 12 Open the isolation valves on the vapor inlet lines and the liquid return line 13 After purge pump out stops or after several minutes return the purge operating mode to Auto or Adaptive recommended using the Tra...

Page 27: ...urge system has a faster air exhaust rate than previous purge systems which makes bypassing or removing the restrictor unnecessary The Daily Pumpout Limit determines how long the purge pump out compressor can operate continuously without generating a Purge Daily Pumpout Exceeded diagnostic which will shut off the purge system You can disable the Daily Pumpout Limit to allow the purge to pump out f...

Page 28: ...rs so on na al l P Pr ro ot te ec ct ti iv ve e E Eq qu ui ip pm me en nt t P PP PE E Diagnostics The chiller controller generates diagnostics to alert the operator to abnormal conditions There are two kinds of diagnostics Non latching diagnostics Operation continues Alarms resolve themselves and the alarm disappears They are informational only Latching diagnostics Operation stops until the condit...

Page 29: ...ed if the purge is functioning correctly If a large amount of air is removed leak test the chiller and repair leaks Consider using the Adaptive mode to run the purge as required when the chiller is Off If non condensable removal is required during chiller operation relocate the vapor liquid connections to a more effective location Pump out restrictor plugged Clean out restrictor orifice with compr...

Page 30: ...gs with an accurate 1 F 0 55 C surface mounted thermocouple type temperature probe that has a range of 40 F 40 0 C to 200 F 93 3 C The locations to be measured are shown in Figure 6 p 16 The temperatures that you should expect to find under typical operating conditions are given in the same figure 1 To ensure accurate measurements remove any ice that may exist on measuring surfaces before attachin...

Page 31: ... to take manual control to test the operation of specific functions Refer to the following table as you test the functions in this section Table 3 Purge component status Displayed purge status Condensing unit Pump out compressor Pump out solenoid Exhaust solenoid Regeneration solenoid Carbon tank heater Refrigerant Circuit On o o o o o Refrigerant Circuit Idle o o o o o o Pumping Out X o o Regener...

Page 32: ...for leaks by using a soap solution 5 Relieve the testing pressure from the exhaust circuit before disabling this test When the test is disabled the exhaust solenoid valve re closes Exhaust Circuit Vacuum Check The Exhaust Circuit Vacuum Check enables the servicing technician to check the exhaust circuit components and lines for leakage by placing a vacuum on the exhaust circuit N No ot te e This t...

Page 33: ...tage 175 W Alarm relay output rating 120 Vac 1 3 hp 7 2 FLA Operating temperature range 34 F to 110 F 1 1 C to 43 3 C Storage temperature range 40 F to 150 F 40 0 C to 65 5 C Storage and operating humidity range 5 to 95 relative humidity non condensing Mounting Direct mounted on condenser shell above the liquid level of highest condenser Dimensions approximate 25 3 4 in 65 4 cm high x 27 1 2 in 69...

Page 34: ...er r l lo oc ck ko ou ut t t ta ag go ou ut t p pr ro oc ce ed du ur re es s t to o e en ns su ur re e t th he e p po ow we er r c ca an n n no ot t b be e i in na ad dv ve er rt te en nt tl ly y e en ne er rg gi iz ze ed d V Ve er ri if fy y t th ha at t n no o p po ow we er r i is s p pr re es se en nt t w wi it th h a a v vo ol lt tm me et te er r N NO OT TI IC CE E U Us se e C Co op pp pe er r...

Page 35: ...PRGD SVX01F EN 35 S Sc ch he em ma at ti ic c W Wi ir ri in ng g D Di ia ag gr ra am m ...

Page 36: ...36 PRGD SVX01F EN S Sc ch he em ma at ti ic c W Wi ir ri in ng g D Di ia ag gr ra am m ...

Page 37: ...PRGD SVX01F EN 37 N No ot te es s ...

Page 38: ...38 PRGD SVX01F EN N No ot te es s ...

Page 39: ...PRGD SVX01F EN 39 N No ot te es s ...

Page 40: ...d protect food and perishables and increase industrial productivity and efficiency We are a global business committed to a world of sustainable progress and enduring results ingersollrand com Ingersoll Rand has a policy of continuous product and product data improvements and reserves the right to change design and specifications without notice We are committed to using environmentally conscious pr...

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